Page:NIOSH Manual of Analytical Methods - 9111.pdf/4

 METHAMPHETAMINE on Wipes by LC/MS : METHOD 9111, Issue 1, dated 17 October 2011 - Page 4 of 12

CALIBRATION AND QUALITY CONTROL: 10.	Determine retention time using the column and chromatographic conditions specified on page 9111-1. 11.	Calibrate daily with at least six media spiked calibration standards and a blank. a.	 Prepare the target analyte spiking solutions. (See SOLUTIONS, 9111-2) b.	 Prepare calibration standards and media blanks in clean shipping containers (e.g. 50-mL polypropylene centrifuge tubes.) c.	 Spike a known volume of target analyte spiking solution into each calibration standard by spiking directly onto the media. Use the spiking volumes suggested in Table 3 to cover the desired range. d.	 Analyze these along with the field samples. (See MEASUREMENT, steps 13-15.) 12.	Prepare matrix-spiked and matrix-spiked duplicate quality control samples (QC and QD). a.	 Cotton gauze from the same lot used for taking samples in the field should be provided to the analytical laboratory to prepare these matrix-spiked QC samples. b.	 The quality control samples (QC and QD) must be prepared independently at concentrations within the analytical range. (See Table 3 for applicable concentration ranges.) c.	 One quality control media blank (QB) must be included with each QC and QD pair. d.	 The quality control samples must be prepared at the rate of one set (QB, QC, and QD) per 20 samples or less. e.	 Transfer clean gauze wipes to new shipping containers. NOTE:		If two gauze wipes were used for the majority of samples in an analytical set, use two clean gauze wipes for each QB, QC, and QD. f.	 Spike QC and QD with a known amount of target analyte as suggested in Table 3. g.	 Process quality control samples along with the calibration standards, blanks, and field samples through steps 7 and 8. h.	 Analyze these along with the calibration standards, blanks, and field samples. (See MEASUREMENT, steps 13-15.) MEASUREMENT: 13.	Analyze the calibration standards, quality control samples, blanks, and samples by LC-MS. a.	 Use the following suggested analytical sequence. i.	 Calibration standards. ii. Matrix spiked quality control samples (QC and QD), one set for every 20 samples or less. iii. A media blank (QB), one for every 20 samples or less. iv. Samples (up to 10) including one sample duplicate. v.	 A continuing calibration verification (CCV) standard consisting of one of the initial calibration standards. vi. A media blank. b.	 Set liquid chromatograph according to manufacturer’s recommendations and to conditions listed previously. c.	 Set mass spectrometer to scan for ions 119, 150, and 164 in SIM mode. Further suggestions for MS conditions are listed in Table 2 but will vary for particular instruments and conditions. See Note 2 in Table 2. d.	 Inject 50 µL of the sample aliquot into liquid chromatograph. e.	 After analysis, the vials should be promptly recapped and refrigerated if further analysis is anticipated. Samples are stable refrigerated for at least seven days. 14.	Using extracted ion current profiles for the primary (quantification) ions specific to methamphetamine and the internal standard, measure the LC peak area of each respective peak and compute relative peak areas by dividing the peak area of the analyte by the area of the internal

Method rev. 1.1.1

NIOSH Manual of Analytical Methods (NMAM), Fifth Edition